[TSP] a performance analysis report about enhanced touchscreen using a sapphire glass.

a performance analysis report about enhanced touchscreen using a sapphire glass.



◆ Introuduction

This document is results of touch performance simulation to apply sapphire glass. Recently, some of smartphone makers has announced the plan to apply sapphire glass through the web news. that reason, most of a smartphone has applied of the chemically strengthened glass to the stylish and thinner design but the customer's enviroment was easily damaged. Therefore a smartphone makers want to use the sapphire for resolve the problem.

◆ The cover glass of dielectric constant

The dielectric constant of the cover glass is used for a touchscreen.
A sapphire material has between 2 to 3 more higher values than a strengthened glass.

※ dielectric constant : relative value about the dielectric constant of vacuum (value = 1)

The experiment verify the impact from a sensitivity of touch to a dielectric constant through the simulation.

◆ Hypothesis
A touchscreen sensitivity revice significant impact to finger size(DFINGER) and cover glass thickness(TGLASS), mutual capacitance(CMUTUAL) between TX and RX.
If the dielectric constant is increased the CFINGER and CMUTUAL Will Be increase. Therefor the sensitivity of touch sensing will be reduced.
a thin glass and a wide finger(DFINGER) would be effective methods for higher sensitivity.

◆ Results

The results are shown below:

◎ Simulation configurations
- Pattern Pitch : 5.00mm x 5.00mm
- Glass Thickness : 0.70mm
- Finger Size : Dia. 4.00mm
- TSP Type : G1F, G2, GFF

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